Armin Shimerman (born November 5, 1949) is an American actor, voice actor and author. Shimerman is known for playing the Ferengi bartender Quark in the television series Star Trek: Deep Space Nine, Principal Snyder in Buffy the Vampire Slayer, Kramer's caddy Stan on Seinfeld, voicing Dr. Nefarious in the Ratchet & Clank series, and Andrew Ryan, one of the antagonists of BioShock. He played Dr. Potter in the 2011 movie adaptation of Ayn Rand's Atlas Shrugged. He also voiced the Agori leader Raanu in Bionicle: The Legend Reborn.